Cracked gas regulator on new stove?

Long time reader, first time poster. Anyways today I was trimming out a kitchen and while tightening a 1/2 male by flare adapter into the stove's regulator I heard a crack, I stopped tightening there and pressurized the line and sure enough the bottom of the pressure regulator had a crack along the female threads. Upon removing the flared adapter I noticed that my pipe dope had only reached about 1/2 way into the fitting and while I was tightening I felt like the adapter was still somewhat loose (I do not believe I was excessively over tightening). Anybody ever seen this? Could the casting on the regulator be faulty? I'm gonna have to swap out the regulator either way (which will be a nightmare) but was just wondering so as to avoid this in the future. I can recall one time that I had a brass 1/2" ball valve crack but never seen or thought it was possible for a regulator.

Often, the gas fitting is a flared fitting which doesn't need to be super tight. If it is a tapered thread, then yes, tight shouldn't be a big deal. If it's a flared fitting, it technically, doesn't need any pipe dope, but you could put a little on the flared face - none needed on the threads.

Regulators usually made of aluminum or some kind of pot metal = soft as hell = don't tighten like you would on steel. Watch out for the chintzy brass
gas shutoffs too, I've had to repair a few of those that got split by plumbers tightening up a nipple too hard.